Being something of a sci-fi nerd, I have for many years had much love for the movie Stargate, and for its spin-off series SG-1. The latter is, for me at least, far superior - or was until some of the later series anyway. The premise had immense scope, and despite the obvious was far less fantastical than the film.
Rather than focusing on a specific character this time, I feel the scepticism inherent in the show is better seen on the level of concepts, outlook and methodology. There are reams of material suitable for examination here, but as I've been working my way through the DVDs of series 2 I expect most of my references will be from there.
Where to begin? Perhaps one of the series' main appeals is that it takes contemporary-minded people and presents them with revelations that turn their understanding of the universe on its head. It does a very good job of exploring how such people would react to these situations - which includes a good deal of scepticism. Evidence is gathered and taken into account, and above all questioned. Everything is subject to reason. It also does a great service not only to the scientific method but to the passion which goes alongside it; in the episode New Ground there is an exchange between Teal'c and a young man from another planet:
Nyan: "You are proof that my theories have been all wrong."
Teal'c: "Then perhaps you would be better off if I were no longer alive."
Nyan: "Teal'c, I am a scientist. When I find evidence that my theories are wrong, it is as exciting as if they were correct. Scientific advance in either direction is still an advance."
And of course, you could hardly find a better avatar of the love and passion for science than Samantha Carter, SG-1's theoretical astrophysicist. It is a tribute to the actress that her eyes actually light up* when she's explaining an exciting new discovery.
What is perhaps the most striking about the general concepts of the show, especially in the earlier seasons, is the juxtaposition of the two main, warring societies: Earth and the Goa'uld. While the former needs little description here, the latter is epitomised by dogma, fanatical religion and unquestioning superstition. Wherever there is fear of their "godlike" powers, the SG-1 team are quick to dispel the myth and deny that there is any magic at work - only superior technology.
There are a few moments in the show which could not be more perfectly symbolic of the scepticism I'm describing. One of these is in the episode Thor's Chariot; a powerful race has protected a people who are approximately at the level of 10th-century Scandinavia, and made provisions for allowing contact when they reach a sufficient level of civilisation. The means of establishing when they have reached this point is a series of tests hidden in a place called the Hall of Thor's Might, which is reached by touching the red stone embedded in an obelisk. SG-1 are told that "it is forbidden to touch the stone".
Isn't that perfect? The first step on the road to civilisation advancement necessarily involves questioning received ideas and mythology. The very activity which is anathema to their parasitic enemies, who run a society based on ideological slavery. Oh, the symbolism!
Anyway, if you've not watched the show, I'd suggest giving it a look - though it can be a trifle silly in places, and stretched the premise to near-breaking point as it aged, there is a great deal of value in it, not least from a scientific, sceptical viewpoint.
* Not literally. That would mean something quite different in the context of the show.